Making backing-plates for artificial teeth



A. H. GUNTHER MAKING BACKING PLATES FOR ARTIFICIAL TEETH.

APPLICATION FILED JUNE 29. I920.

Patented May 10, 1921.

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Jig. 12 @142 INVENTOR I I ATTORNEYS A; H. GUNTHERF MAKINGBACKING PLATES FOR ARTIFICIAL TEETH.

APPLICATI N FILED JUNE 29. I920- v 1,377,474. Patented May 10,1921.

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IIIIIIIIIIHIIIIIIIIIIIIIIIIIII Z1 UNITED STA-T513 AMI HENRY GUNTHER, 0F CHILLICOTHE, OHIO.

MAKING BACKING-PLATES FOR ARTIFICIAL TEETH.

Specification of Letters Patent.

Application filed June 29, 1920. Serial No. 392,728.

T 0 aZZ n/wm it may concern.

Be it known that I, Am HENRY GUN- arrnn, a citizen of the United States of America residing at Chillicothe, in the county of Ross and State of Ohio, have invented certain new and useful Improvements in Making Backing-Plates for Artificial Teeth, of which the following is full, clear, and exact description. 1

This invention relates to backing plates for artificial teeth used in dental bridges, and its chief object is to provide a simple, con venient and effective method and apparatus by which the dentist himself can make backing plates of the highest quality at practically no greater expense than the cost of the materials used, thus effecting a very considerable saving. To this and other ends the invention consists in the novel features hereinafter described.

Referring to the accompanying drawings, Figure 1 is a perspective view and Fig. 2 a side view illustrating two common types of backing plates which can be made easily, rapidly and cheaply by means of my'invention.

Fig. 3- is a side View of an improved diepress devised by me for usein my method.

Fig. 4 is a cross section on line 1-i of Fig.5 is a detail sectional plan view on line 5-5 of Fig. 1.

Fig- 6 is an edgewise view of the lower die used in the preliminary cutting and shaping of the sheet metalv blank from which the backing plate is made.

Fig. 7 is a plan view of the rectangular sheet metal blank before it has received its first cutting and shaping in thediepress, and Figs. 8 and 9 are plan and end views, respectively, of the blank after these operations have been performed.

Fig. 10 is a perspective view of a convenient tool which is usefulin my process.

Figs. 11 12, 13, 14 and 15 illustrate successive steps in, the making of the backing plate after the blank has been out and shapedas in Fig. 8.

Fig. 16 is a face view of one of the shaping dies as modified to produce a backing plate of the type shown in Fig. 2, and Fig.

17 is a plan view illustrating a blank as notched or recessed for that'type.

The backing plate illustrated in Fig. 1 consists of a sheet metal plate 10 having I into a groove 28.

a locking rib 11 parallel to the plate and connected thereto by a web 12. In the particular device shown in Fig. 1 the web 12 is flush with the end of the rib and the lower edge of the plate, but at the other end it preferably terminates below the end of the rib, as shown, the rib itself being materially shorter than the plate.

In making a. backing plate in the preferred manner I use a rectangular blank of sheet metal, for example gold of suitable gage and fineness, as for illustration a blank such as is shown at 13, Fig. 7. The next step is to cut in one side or end a, square or rectangular notch 14, Fig. 8, with a central projection or tongue 15 at its bottom, and to form a shallow groove 16 extending, lengthwis from the center of the tongue. The notch and groove are preferably formed in one, operation by means of the diepress illustrated inFigs. 3, 4;, 5 and 6., As there shown, the diepress comprises a substantial base 17 composed of a rectangular block of steel or other suitable metal, having at one end a pair of standards 18 supporting at th top an overhanging carrier 19 in which is mounted a vertically re'ciprocatory plunger 20. Removably embedded in the base immediately under the plunger is a lower die 21, having at its front edge a recess 22 with a central projection 23. In the face of the die, and extending straight back from the center of the projection 23 is a shallow groove 2 1. The upper die is formed on the lower end of the plunger, and at its forward end it is provided with a downwardly projecting punch 25 corresponding in shape to the recess 22 and tongue 23. In rear of the punch is a rounded rib 26 to cooperate with the groove 24 in the lower die. The plunger is guided and prevented from rotating in its re-ciprocatory movement by a stud 27 extending throughthe collar 19 At its lower end. the groove is formed with a lateral enlargement 29 so that when the plunger is raised and given a slight'turn the guide stud will enter the enlargement and thereby support the plunger in its upper position. The recess 22 in th lower die opens into a vertical passage 30 which in turn opens into a transverse passage 31 in the base 17 to re ceive the cuttings from the die.

The blank 13, Fig. 7, having been prepared, it is placed centrally onthelower Patented May 10, 1921. 7

die, with the edge of the blank againstthe stop-shoulder 32, and the plunger is lowered until the punch 25 rests on the blank. The plunger is then struck a smart blow with the palm of the hand. This drives the punch into the recess 22, thereby cutting the notch 14 in the blank (see Fig. 8). At the same time the rib 26 and groove 24 form the groove 16 at the center of the blank.

For the next operation I use an instrument of the type illustrated in Fig. 10, consisting of a flat piece of hard metal 33 formed at one end with a knife-edge 34 and at its other with a rib 35 constituting a mandrel. The latter is placed in the groove 16, Fig. 11, and the sides of the blank are then bent up in the direction of the arrows, giving the blank the U form indicated in Fig. 12, after which the instrument 33 removed and a mandrel of suitable size, as a piece of wire 36, Fig. 13, is laid in the bight.

The next step is to compress and shape the blank around the wire 36, and for this purpose I employ the compressing and shaping dies 37, 38, Figs. 3, 14 and 15. These dies are mounted on the block 17, which at its right end is split to form a movable jaw 17 actuated by a screw 39 threaded in the block and rotatable in the jaw by means of a handle but incapable of axial movement. Thejaw is guided by two parallel arms 41, 42, working in grooves 43 in the sides of the block 17. The dies 3'7, 38 extend transversely of the block and in their opposite. faces. they are provided with parallel grooves 43, 44, the upper edges of which are cut back so that when the two dies are brought together a space will be left between said upper edges.

The folded blank, with the wire 36 in place, is inserted between the dies 37, 38, as in F ig. 14, and the jaws are brought firmly together by means of the screw 39, thereby wrapping the bight of the blank snugly around the wire and pressing into close contact the portions of the blank immediately above the wire, as clearly indicated in Fig. 15. Inserting the edge 34 of the instrument 33 between the upstanding sides of the blank, the latter are bent down to the dotted line position, the bends being made by the edges of the dies, along the dotted lines 37, 38, (Fig. 8) spaced from the groove 16, to form the web 11. Laying "the instrument33 or other'flat piece of metal or hard wood on the wings of the; blank a few light blows with a hammer serve to flatten the wings accurately in a single plane on the smooth upper surface of the dies.

The backing plate is now in the form shown in Fig. 1; it being understood that the dies 25 and 21, 37 and 38, are so proportioned that with the proper gage of metal used for the plate and with the wire 36 properly chosen as to diameter, the side edges of the tongue 15 will just come together and the side edges of the notch or recess 14 will come flush with the top of the dies 37, 38 when the latter are brought together' to the position shown in Fig. 15, thus having these edges in contact when the sides of the blank are flattened out, as indicated by the line 45, Fig. 1. The wire 36 may be withdrawn, but I prefer to leave it and out it off flush with or extending slightly beyond either or both ends of the tubular rib 11, soldering it in place if desired. I also prefer to flow solder or gold along the joint 45, at the back of the plate, and intothe shallow groove 46 left at the back along the web 11, Fig. 15.

For making the type of backing plate illustrated in Fig. 2 the die 21 and punch 25, Figs. 3 and 5, are modified so that the side edges of the recess 14 out in the blank, will flare outwardly as in Fig. 17, and the grooves in the dies 37 38, are inclined to the upper surface as indicated at 43 Fig. 16, so that the sides of the blank will be bent along the converging dotedlines when flattened down on the dies.

It is to be understood that the invention is not limited to the specific details herein illustrated and described but can be modified widely without departing from its spirit.

What I claim as my invention is:

1. In the art of making backing plates for artificial teeth, the improvement. comprising cutting in the edge of'a sheet metal blank a notch or recess havinga tongue extending into the recess from the inner or bottom edge thereof, bending the blank in line with the tongue to produce a tubular rib with the tongue forming one end thereof, and bending the sides of the blank outwardly along lines spaced laterally from the rib to form a back plate with the rib' connected thereto by an intermediate web shorter than the rib itself.

2. In the art of making backing plates for artificial teeth, the improvement comprising cutting in the edge ofa sheet metal blank a notch or recess having a tongue extending into the recess from the inner edge thereof and simultaneously bending the blank to form a groove extending rearwardly from the front edge of the tongue to the rear edge of the blank, bending the sides of the blank around a mandrel in said groove to form a tubular rib, and bending the sides of the blank outwardly along lines spaced from said rib to form a back plate with the rib connected thereto by an inter mediate web shorter than the rib itself.

3. In the art of making backing plates for artificial teeth, the improvement comprising die-cutting in the edge of a sheet metal blank a notch or recess having a tongue extending into the recess from the inner edge thereof, and simultaneously diepressing in the blank a groove extending rearwardly from the front edge of the tongue to the rear edge of the blank; bending the blank to U-shape upon a mandrel placed in the groove; compressing the sides of the blank around a mandrel arranged in the bottom of the U to form a tubular rib; andbending the sides of the blank outwardly along lines spaced from the rib to form a back plate With the rib connected thereto by an intermediate Web shorter than the rib itself.

4:. In the art of making backing plates for artificial teeth, the improvement comprising cutting in the edge of a sheet metal blank a notch or recess having a tongue extending into the recess from the inner edge thereof, bending the blank around a mandrel arranged 0n and in line With the tongue to form a tubular rib with the side edges of the tongue in contact with each other, and bending the sides of the blank outwardly along lines coincident with the side edges of said recess to form a back plate With the tubular rib connected thereto by an intermediate web in length shorter than the rib itself and in width substantially equal to the space between a side edge of the said recess and the adjacent side edge of said ton ue.

5. In the art 0 making backing plates for artificial teeth, the improvement comprising cutting a notch or recess in the edge of a sheet metal blank, bending the notched blank.

around a wire mandrel arranged onsand in line with the tongue to form a tubular rib, in part composed of the tongue and in part composed of the body of the blank, and bending the sides of the blank outwardly along lines coincident with the side edges of said notch to form a back plate with the edges of the rib closely adjacent to each other and with the rib connected to said back plate by an intermediate web.

6. In the art of making backing plates for artificial teeth, the improvement comprising cutting a notch or recess in the edge of a sheet metal blank, bending the notched blank around a wire mandrel to form a tubular rib, bending the sides of the blank outwardly along lines coincident with the side edges of said notch to form a back plate with the tubular rib connected thereto by an intermediate web, and securing the Wire permanently in the tubular rib.

In testimony whereof I hereto aflix my signature.

AMI HENRY GUNTHER. 

